Integrated building based air handler for server farm cooling system

ABSTRACT

An air handler building structure is disclosed, which includes a floor, a plurality of lateral walls, a roof, and one or more openings located either on the roof or on at least one of the lateral walls. The lateral walls include a lower and an upper lateral walls opposing to each other having different respective heights determined in accordance with a ratio. The roof has a pitch consistent with the ratio associated with the lower and upper lateral walls. The shape of the building structure allows air within the building structure to rise via natural convection. In addition, a first dimension along a first direction defined between the lower and upper lateral walls relative to a second dimension along a second direction perpendicular to the first direction is such that the building structure provides access to outside natural air via one or more openings on the lower lateral wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 13/230,809 filed Sep. 12, 2011 entitled,INTEGRATED BUILDING BASED AIR HANDLER FOR SERVER FARM COOLING SYSTEM,which is a continuation in part (CIP) of and claims priority to U.S.patent application Ser. No. 12/500,520 filed Jul. 9, 2009 entitled,INTEGRATED BUILDING BASED AIR HANDLER FOR SERVER FARM COOLING SYSTEM,all of which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates generally to cooling systems.

BACKGROUND

The rapid growth of Internet services such as Web email, Web search, Website hosting, and Web video sharing is creating increasingly high demandfor computing and storage power from servers in data centers. While theperformance of servers is improving, the power consumption of servers isalso rising despite efforts in low power design of integrated circuits.For example, one of the most widely used server processors, AMD'sOpteron processor, runs at up to 95 watts. Intel's Xeon server processorruns at between 110 and 165 watts. Processors are only part of a server,however; other parts in a server such as storage devices consumeadditional power.

Servers are typically placed in racks in a data center. There are avariety of physical configurations for racks. A typical rackconfiguration includes mounting rails to which multiple units ofequipment, such as server blades, are mounted and stacked verticallywithin the rack. One of the most widely used 19-inch rack is astandardized system for mounting equipment such as 1U or 2U servers. Onerack unit on this type of rack typically is 1.75 inches high and 19inches wide. A rack-mounted unit that can be installed in one rack unitis commonly designated as a 1U server. In data centers, a standard rackis usually densely populated with servers, storage devices, switches,and/or telecommunications equipment. One or more cooling fans may bemounted internally within a rack-mounted unit to cool the unit. In somedata centers, fanless rack-mounted units are used to increase densityand to reduce noise.

Rack-mounted units may comprise servers, storage devices, andcommunication devices. Most rack-mounted units have relatively wideranges of tolerable operating temperature and humidity requirements. Forexample, the system operating temperature range of the Hewlett-Packard(HP) ProLiant DL365 G5 Quad-Core Opteron processor server models isbetween 50° F. and 95° F.; the system operating humidity range for thesame models is between 10% and 90% relative humidity. The systemoperating temperature range of the NetApp FAS6000 series filers isbetween 50° F. and 105° F.; the system operating humidity range for thesame models is between 20% and 80% relative humidity. There are manyplaces around the globe such as parts of the northeast and northwestregion of the United States where natural cool air may be suitable tocool servers such as the HP ProLiant servers and the NetApp filersduring certain periods of a year.

The power consumption of a rack densely stacked with servers powered byOpteron or Xeon processors may be between 7,000 and 15,000 watts. As aresult, server racks can produce very concentrated heat loads. The heatdissipated by the servers in the racks is exhausted to the data centerroom. The heat collectively generated by densely populated racks canhave an adverse effect on the performance and reliability of theequipment installed in the racks, since they rely on the surrounding airfor cooling. Accordingly, heating, ventilation, air conditioning (HVAC)systems are often an important part of the design of an efficient datacenter.

A typical data center consumes 10 to 40 megawatts of power. The majorityof energy consumption is divided between the operation of servers andHVAC systems, HVAC systems have been estimated to account for between 25to 40 percent of power use in data centers. For a data center thatconsumes 40 megawatts of power, the HAVC systems may consume 10 to 16megawatts of power. Significant cost savings can be achieved byutilizing efficient cooling systems and methods that reduce energy use.For example, reducing the power consumption of HVAC systems from 25percent to 10 percent of power used in data centers translates to asavings of 6 megawatts of power which is enough to power thousands ofresidential homes. The percentage of power used to cool the servers in adata center is referred to as the cost-to-cool efficiency for a datacenter. Improving the cost-to-cool efficiency for a data center is oneof the important goals of efficient data center design. For example, fora 40 megawatt data center, the monthly electricity cost is about $1.46million assuming 730 hours of operation per month and $0.05 per kilowatthour. Improving the cost to cool efficiency from 25% to 10% translatesto a saving of $219,000 per month or $2.63 million a year.

In a data center room, server racks are typically laid out in rows withalternating cold and hot aisles between them. All servers are installedinto the racks to achieve a front-to-back airflow pattern that drawsconditioned air in from the cold rows, located in front of the rack, andejects heat out through the hot rows behind the racks. A raised floorroom design is commonly used to accommodate an underfloor airdistribution system, where cooled air is supplied through vents in theraised floor along the cold aisles.

A factor in efficient cooling of data center is to manage the air flowand circulation inside a data center. Computer Room Air Conditioners(CRAC) units supply cold air through floor tiles including vents betweenthe racks. In addition to servers, CRAC units consume significantamounts of power as well. One CRAC unit may have up to three 5horsepower motors and up to 150 CRAC units may be needed to cool a datacenter. The CRAC units collectively consume significant amounts of powerin a data center. For example, in a data center room with hot and coldrow configuration, hot air from the hot rows is moved out of the hot rowand circulated to the CRAC units. The CRAC units cool the air. Fanspowered by the motors of the CRAC units supply the cooled air to anunderfloor plenum defined by the raised sub-floor. The pressure createdby driving the cooled air into the underfloor plenum drives the cooledair upwardly through vents in the subfloor, supplying it to the coldaisles where the server racks are facing. To achieve a sufficient airflow rate, hundreds of powerful CRAC units may be installed throughout atypical data center room. I-However, since CRAC units are generallyinstalled at the corners of the data center room, their ability toefficiently increase air flow rate is negatively impacted. The cost ofbuilding a raised floor generally is high and the cooling efficiencygenerally is low due to inefficient air movement inside the data centerroom. In addition, the location of the floor vents requires carefulplanning throughout the design and construction of the data center toprevent short circuiting of supply air. Removing tiles to fix hot spotscan cause problems throughout the system.

SUMMARY

The present teaching relates to cooling systems.

In one example, an air handler building structure is disclosed, whichincludes a floor, a plurality of lateral walls, a roof, and one or moreopenings located either on the roof or on at least one of the lateralwalls. The lateral walls include a lower and an upper lateral wallsopposing to each other having different respective heights determined inaccordance with a ratio. The roof has a pitch consistent with the ratioassociated with the lower and upper lateral walls. The shape of thebuilding structure allows air within the building structure to rise vianatural convection. In addition, a first dimension along a firstdirection defined between the lower and upper lateral walls relative toa second dimension along a second direction perpendicular to the firstdirection is such that the building structure provides access to outsidenatural air via one or more openings on the lower lateral wall.

In another example, a server cooling system is disclosed, which includesa first space defined by a floor, one or more lateral walls, and aceiling, having a plurality of servers installed therein, and secondspace defined by the ceiling and a roof. One or more openings arelocated on at least one of the ceiling, the roof, and at least one ofthe one or more lateral walls. The server cooling system also includesan air inlet coupled with a first lateral wall and operable to allowoutside natural air to enter, one or more air-handling units coupledwith the air inlet to draw the outside natural air and to provide air tothe first space, and an air outlet coupled with a second lateral walland operable to allow air in the second space to exit. The servercooling system further includes a control system configured to controlthe one or more air-handling units to provide air to the first space inaccordance with temperatures measured within and outside of the firstspace.

In still another example, a server cooling system is disclosed, whichincludes a first space defined by a floor, a plurality of lateral walls,and a ceiling, and a second space defined by the ceiling and a slopedroof constructed in accordance with a pitch. One or more openings arelocated on at least one of the roof, the ceiling, and at least one ofthe lateral walls, that enable outside natural air to enter the firstspace and air in the second space to exit by natural convection. Theserver cooling system also includes an interior space inside the firstspace, that is substantially enclosed and engaging the ceiling, and arack engaging the interior space in a substantially sealed manner andhaving a plurality of rack-mounted servers mounted thereon. Respectivefront faces of the rack-mounted servers interface with the first spacerespective back faces of the rack-mounted servers interface with theinterior space. Each rack-mounted server includes one or more fansinstalled therein operable to draw air from the first space through itsfront face and expel heated air to the interior space through its backface.

In yet another example, an air handler building structure is disclosed,which includes a floor, a plurality of lateral walls, a roof portion, aprotruding portion, and one or more openings located on at least one ofthe roof portion, at least one of the lateral walls, and the protrudingportion. The roof portion has opposing sides, each having a pitch. Theprotruding portion extends above the roof portion. In addition, theshape of the building structure allows outside natural air to enterthrough one or more openings on at least one of the lateral walls vianatural convection and exit through one or more openings on at least oneof the roof portion and the protruding portion.

The following detailed description together with the accompanyingdrawings will provide a better understanding of the nature andadvantages of various embodiments of the present invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an exemplary, server cooling system;

FIG. 2 is a diagram showing an example server cooling system wherein theserver cooling system comprises an attic space;

FIG. 3 is a diagram showing an example server cooling system wherein airis re-circulated inside the example server cooling system;

FIG. 4 is a diagram showing an example server cooling system with a hotrow enclosure and a cold row enclosure;

FIG. 5 is a diagram showing an example server cooling system with a hotrow enclosure and a cold row enclosure wherein air is re-circulatedinside the a server cooling system;

FIG. 6 is a diagram showing an example server cooling system with asingle-sloped roof;

FIG. 7 is a diagram showing a top view of an example server coolingsystem with a single-sloped roof;

FIG. 8 is a diagram showing an example server cooling system with agable roof;

FIG. 9 is a diagram showing an example server cooling system with an airmixing chamber;

FIGS. 10A and 10B are diagrams showing an example air handler buildingstructure;

FIG. 11 is a diagram showing an example server cooling system;

FIG. 12 is a diagram showing another example server cooling system;

FIG. 13 illustrates a cross-section of an other example of an airhandler building structure; and

FIG. 14 illustrates a cross section of yet another exemplary air handlerbuilding structure.

DESCRIPTION OF EXAMPLE EMBODIMENT(S)

The following example embodiments and their aspects are described andillustrated in conjunction with apparatuses, methods, and systems whichare meant to be illustrative examples, not limiting in scope.

FIG. 1 illustrates an example server cooling system comprising lateralwalls 100, a floor 102, a roof 104, an enclosure 106, and a server rack108. The lateral walls 100, the floor 102 and the roof 104 define aninside space 118. Floor 102 may or may not be a raised sub-floor. Theremay be valved openings 110 on the roof 104 and valved openings 114 onthe lateral walls 100. The valved openings may be connected to a controlsystem which is operable to selectively open or close each valvedopening. The enclosure 106 may have a frame, panels, doors, and serverrack ports. A server rack port is an opening in the enclosure 106 thatcan be connected to one or more server racks 108. The enclosure 106 maybe made of a variety of materials such as steel, composite materials, orcarbon materials that create a housing defining an interior space 116that is substantially sealed from the inside space 118. The enclosure106 comprises at least one server rack port that allows one or morerack-mounted units installed in the server rack 108 to interface withthe interior space 116. In one implementation, the a server rack port isan opening configured to substantially conform to the outer contours of,and accommodate, a server rack 108. One or more edges of the server rackport may include a gasket or other component that contacts the serverrack 108 and forms a substantially sealed interface. The server rack 108may be removably connected to the enclosure 106 through the server rackport in a substantially sealed manner. In some embodiments, one or morerack-mounted units are installed in the server rack 108 such thatrespective front faces of the rack-mounted units interface with theinside space 118, and that respective back faces of the rack-mountedunits interface with the interior space 116 defined by the enclosure106. An example rack-mounted unit may be a server blade, data storagearray or other functional device. A front-to-back air flow through therack-mounted units installed in the server rack 108 draws cooling airfrom the inside space 118 and expels heated air to the interior space116.

The enclosure 106 may be connected to valved openings 110 on the roof104 through a connector 112 on a top side of the enclosure. In someembodiments, the connector 112 may be made of metal ducts. In otherembodiments, the connector 112 may be made of soft and flexiblematerials so that the enclosure may be removably connected to the valvedopenings 110. In some embodiments, the enclosure 106 may be mounteddirectly to the floor 102. In other embodiments, the enclosure 106 mayhave wheels on the bottom side and may be easily moved around in a datacenter.

In some embodiments, the server rack 108 may be sparsely populated withservers and other equipment. Since servers and other equipment arestacked vertically within the rack, the scarcity may create open gaps tothe interior space 116. Air may leak from the interior space 116 throughthe open gaps. To prevent air leakage, the gaps may be blocked by panelsmounted to the server rack 108 that prevent air from escaping andentering the enclosure 106 through the gaps.

In some embodiments, one or more air handling units 122 may drawexternal cool air into the inside space 118. The cool air enters theserver cooling system through valved openings 114 on the lateral walls100. One or more fans draw the cool air from the inside space 118through the front faces of the one or more rack-mounted units and expelheated air through the back faces of the one or more rack-mounted unitsto the interior space 116. The heated air passes through the connector112 and leaves the interior space 116 through the valved openings 110 onthe roof 110. In some embodiments, the cooling fans mounted internallywithin the rack-mounted units installed in the rack 108 draw the coolair from the inside space 118 and expel heated air to the interior space116; no additional air handling units, in one implementation, are needto cool the rack-mounted units. In other embodiments where fanlessrack-mounted units are installed in the rack 108, one or more fans maybe installed on one side of the rack 108 to draw air through therack-mounted units from the inside space 118 to the interior space 116to cool the rack-mounted units installed in the rack 108.

In some embodiments, there may be valved openings 120 on the enclosure116. A control system is operably connected to the valved openings 120,the valved openings 110 on the roof 104, and the valved openings 114 onthe lateral walls 100. The control system is operable to selectivelyactivate each of the valved openings based on temperatures observedwithin and outside the inside space 118 to achieve one or more desiredair flows. When the air external to the inside space 118 is not suitableto be introduced to the inside space 118, the control system closes thevalved openings 110 and 114, and opens up the valved openings 120. Tocool air in the inside space 118, one or more cooling units may be used.In some embodiments, the cooling units may be evaporative coolers whichare devices that cool air through the simple evaporation of water.Compared with refrigeration or absorption air conditioning, evaporativecooling may be more energy efficient. Cooling air is drawn from theinside space 118 through the rack-mounted units and heated air isexpelled to the interior space 116 defined by the enclosure 106. Heatedair inside the enclosure 106 is exhausted to the inside space 118through the valved openings 120. In some embodiments, one or more fansmay be used to exhaust the heated air out of the enclosure 106.

In other embodiments, one or more cooling units may be used whileexternal air is introduced to the inside space 118. The control systemmay open the valved openings 110, 114, and 120 simultaneously.Evaporative cooling units may be used in close proximity to the valvedopenings 114 so that the external air may be cooled while beingintroduced to the inside space 118.

In yet other embodiments, the control system may open the valvedopenings 110, and close valved openings 114 and 120 when the differencein temperature between the outside and the insider space reaches certainconfigurable threshold values. In other embodiments, the control systemmay close valved openings 110, and open up valved openings 114 and 120.To cool the air in the inside space 120, one or more evaporative coolingunits may be placed in the inside space 120 to provide cooling.

In some embodiments, the roof 104 comprises a single-sloped roof whichmay be easy to manufacture and install. In other embodiments, othertypes of roof configurations, such as a gable roof, may be used. Thelateral walls 100, the floor 102, and the roof 104 may bepre-manufactured in a factory and assembled on the construction sitewhere a data center is to be built. Pre-manufactured units maysignificantly reduce the cost to build a data center. One of the costadvantages of the integrated building based air handler for server farmcooling system is the convenience and low cost of pre-manufacture partsof the system and the ease of installation of pre-manufactured parts ina data center.

In some embodiments, the integrated building based air handler forserver farm cooling system illustrated in FIG. 1 obviates the need forraised subfloors, CRAC units and water chillers. A large number of partsof the cooling system may be pre-manufactured and easily assembled.Natural cool air may be used to cool the servers. Cooling fans installedinternally within the servers may provide the needed air flow to drawcooling air to cool the servers; CRAC units and raised subfloors may nolonger be needed. Efficient evaporative coolers may replace the waterchillers which are costly to install and operate. Overall, the coolingsystems described herein may significantly reduce the construction cost,and electricity power and water usage, of server farm deployments.

FIG. 2 illustrates another example server cooling system comprisinglateral walls 200, a floor 202, a roof 204, an enclosure 206, a serverrack 208, and a ceiling 210. The example cooling system in FIG. 2 issimilar to that in FIG. 1 except that the ceiling 210 and the roof 204define an attic space 220. The lateral walls 200, the floor 202 and theceiling 210 define an inside space 218. One or more valved openings 222are coupled to the ceiling 210. There may be valved openings 224 on theroof 204 and valved openings 214 on the lateral walls 200. The enclosure206 is operably connected to the attic space 220 through a connector212.

In some embodiments, one or more air handling units 226 may drawexternal cool air into the inside space 218. One or more fans draw thecool air from the inside space 218 through the front faces of the one ormore rack-mounted units installed in the rack 208 and expel heated airthrough the back faces of the rack-mounted units to the interior space216. The heated air passes through the connector 212 and enters theattic space 220. In some embodiments, the cooling fans mountedinternally within the rack-mounted units installed in the rack 208 drawthe cooling air to the interior space 216 and no additional air handlingunits are needed. In other embodiments where fanless rack-mounted unitsare installed in the rack 208, one or more fans may be installed on oneside of the rack 208 to draw air from the inside space to the interiorspace 216 to cool the rack-mounted units installed in the server rack208. Heated air rises to the attic space 220 and is exhausted out of thecooling system through the valved openings 224.

FIG. 3 illustrates another example server cooling system comprisinglateral walls 300, a floor 303, a roof 304, an enclosure 306, a serverrack 308, and a ceiling 310. The lateral walls 300, the floor 302 andthe ceiling 310 define an inside space 318. The roof 304 and the ceiling310 define an attic space 330. One or more valved openings 322 arecoupled to the ceiling 310. There may be valved openings 324 on the roof304 and valved openings 314 on the lateral walls 300. The enclosure 306is operably connected to the attic space 320 through a connector 312.The example cooling system in FIG. 3 is similar to that in FIG. 2 exceptthat external air may not be introduced into the inside space 318 andthat heated air in the attic space 330, at some points in time, may notbe exhausted to the outside of the example server cooling system;rather, the heated air may be mixed into the inside space 318 as neededto maintain a desired operating temperature.

In one embodiment, the valved openings 322, 324, and 314 are connectedto a control system which is operable to selectively activate each ofthe valved openings based on temperatures observed within and outsidethe inside space 318. When the external air is not suitable to beintroduced to the inside space 318, the control system closes the valvedopenings 314 and 324, and opens up the valved openings 322. To cool airin the inside space 318, one or more cooling units may be used. In someembodiments, the cooling units may be evaporative coolers. Cooling airis drawn from the inside space 318 through the rack-mounted units andthe heated air is expelled to the interior space 316 defined by theenclosure 306. Heated air inside the enclosure 306 is exhausted to theattic space 320 through the connector 312 and re-circulated to theinside space 318 through the valved openings 322 coupled to the ceiling310. In some embodiments, one or more fans may be used to exhaust theheated air out of the enclosure 306 to the attic space 320 and/orre-circulate at least some of the heated air to the inside space 318.

In other embodiments, one or more cooling units may be used while theexternal air is introduced to the inside space 318. The control systemmay open the valved openings 314, 322, and 324 simultaneously or atselected times individually. Evaporative cooling units may be used inclose proximity to the valved openings 314 so that external air may becooled while being introduced to the inside space 318.

In yet other embodiments, the control system may open up the valvedopenings 314 and 322, and close the valved openings 324. Evaporativecooling units may be used in close proximity to the valved openings 314and/or the valved openings 322 to provide efficient cooling in theinside space 318. In other embodiments, the control system may closevalved openings 314, and open up valved openings 322 and 324. In oneembodiment, the control system may close valved openings 314 and 322,and open up the valved openings 324. The control system monitors thetemperatures within the inside space 318, within the attic space 320 andthe temperature outside. When the difference among the three observedtemperatures reaches one or more configurable threshold vales, thecontrol system may selectively open up or close each valved opening.

FIG. 4 illustrates another example server cooling system comprisinglateral walls 400, a floor 402, a roof 404, a hot row enclosure 406, aserver rack 408, a cold row enclosure 410, and a ceiling 424. Theexample cooling system in FIG. 4 is similar to that in FIG. 3 exceptthat one or more cold row enclosures are used to provide efficientcooling of servers installed in the rack 408.

The lateral walls 400, the floor 402 and the ceiling 424 define aninside space 418. The ceiling 424 and the roof 404 define an attic space420. In some embodiments, one or more valved openings 426 may be coupledto the ceiling 424. In some other embodiments, the hot row enclosure 406comprises at least one server rack port that allows one or morerack-mounted units to interface with a hot row interior space 416. Thecold row enclosure 410 also comprises at least one server rack port thatallows one or more rack-mounted units to interface with a cold rowinterior space 422. The server rack 408 may be removably connected tothe hot row enclosure 406 through the server rack port in asubstantially sealed manner. The server rack 408 may also be removablyconnected to the cold row enclosure 410 through the server rack port ina substantially sealed manner. In some embodiments, the rack-mountedunits are installed in the server rack 408 such that respective frontfaces of the rack-mounted units interface with the cold row interiorspace 422, and that respective back faces of the rack-mounted unitsinterface with the hot row interior space 416. In some embodiments, thehot row enclosure 406 may be operably connected to the attic space 420through a connector 412. In some other embodiments, the cold rowenclosure may comprise a fan unit 430 to draw air from the cold rowinterior space 422 through the front faces of the rack-mounted unitsinstalled in the rack 408 to cool the rack-mounted units; the heated airis ejected to the hot row interior space 416 through the back faces ofthe rack-mounted units.

In some embodiments, one or more air handling units 432 may drawexternal cool air into the inside space 418. The cool air enters theserver cooling system through valved openings 414 on the lateral walls400. The one or more fans 430 draw the cool air from the inside space418 to the cold row interior space 422 through one or more openings onthe cold row enclosure 410. In some embodiments, each cold row enclosure410 may be operably connected to the valved openings 414 so that theexternal cool air may be drawn to the cold row interior space 422. Insome other embodiments, the cooling fans mounted internally within therack-mounted units draw the cool air from the cold row interior space422. The cool air flows through the front faces of the one or morerack-mounted units installed in the rack 408 and expel heated airthrough the back faces of the one or more rack-mounted units to hot rowinterior space 416. The heated air passes through the connector 412 andenters the attic space 420. In some embodiments, the heated air insidethe attic space 420 may be exhausted out of the cooling system throughthe valved openings 428.

In some embodiments where fanless rack-mounted units are installed inthe rack 408, one or more fans may be installed on one side of the rack408 to draw air from the inside space 418 to the interior space 416 tocool the rack-mounted units installed in the rack 408. In otherembodiments, the one or more fans 422 may provide the needed power forthe cool air to flow from the cold row interior space 422 to the hot rowinterior space 416.

FIG. 5 illustrates another example server cooling system comprisinglateral walls 500, a floor 502, a roof 504, a hot row enclosure 506, aserver rack 508, a cold row enclosure 510, and a ceiling 524. Thelateral walls 500, the floor 502 and the ceiling 524 define an insidespace 51. The ceiling 524 and the roof 504 define an attic space 520.The example cooling system in FIG. 5 is similar to that in FIG. 4 exceptthat external air may not be introduced into the inside space 518 andthat heated air in the attic space 520 may not be exhausted to theoutside of the example server cooling system.

In some embodiments, one or more valved openings 526 may be coupled tothe ceiling 524. The valved openings 514, 528, and 526 are operablyconnected to a control system which is operable to selectively activateeach of the valved openings based on temperatures observed within andoutside the inside space 518 and/or the attic space 520. When theexternal air is not suitable to be introduced to the inside space 518,the control system closes the valved openings 514 and 528, and opens upthe valved openings 526. To cool air in the inside space 518, one ormore cooling units 532 may be used. In some embodiments, the coolingunits 532 may be evaporative coolers. Cooling air is drawn from theinside space 518 to the cold row interior space 522. In someembodiments, one or more fans 530 may be used to draw cooling air intothe cold row enclosure 510. The cooling air is drawn from the cold rowinterior space 522 through the rack-mounted units installed in the rack508; the heated air is expelled to the hot row interior space 516defined by the enclosure 506. Heated air enters the attic space 520through the connector 512 and is re-circulated to the inside space 518through the valved openings 526 coupled to the ceiling 524. In someembodiments, one or more fans may be used to exhaust the heated air outof the enclosure 506 to the attic space 520 and re-circulated to theinside space 518

FIG. 6 illustrates a three dimensional view of an example server coolingsystem comprising lateral walls 600, a floor 602, a roof 604, anenclosure 606, a server rack 608, and a ceiling 610. The lateral walls600, the floor 602 and the ceiling 610 define an inside space 618. Theroof 604 and the ceiling 610 define an attic space 620. The enclosure606 defines an interior space 616. One or more valved openings 622 arecoupled to the ceiling 610. There may be valved openings 624 on the roof604 and valved openings 614 on the lateral walls 600. The enclosure 606is operably connected to the attic space 620 through a connector 612. Insome embodiments, one or more rack-mounted units are installed in therack 608 such that respective front faces of the rack-mounted unitsinterface with the inside space 618, and that respective back faces ofthe rack-mounted units interface with the interior space 616. In someembodiments, external cool air may be drawn into the inside space 618through valved openings 614. The cool air may be drawn from the insidespace 618 by cooling fans mounted internally within the rack-mountedunits installed in the rack 608; the heated air is ejected into theinterior space 616 and enters the attic space 620 through the connector612. In other embodiments where fanless rack-mounted units are installedin the rack 608, one or more fans may be used to draw cooling air fromthe inside space 618 to the interior space 616. In some embodiments, theair handling units 626 may be used to draw external cool air to theinside space 618 through valved openings 614. The valved openings 614,624, and 622 are operably connected to a control system which isoperable to selectively activate each of the valved openings based ontemperatures observed within and outside the inside space 618 and/or theattic space 620. When the external air is not suitable to be introducedto the inside space 618, the control system closes the valved openings614 and 624, and opens up the valved openings 622. To cool air in theinside space 618, one or more cooling units may be used. In someembodiments, the cooling units may be evaporative coolers. The cooledair is drawn from the inside space 618 through the rack-mounted unitsand installed in the rack 608; the heated air is expelled to theinterior space 616. Heated air enters the attic space 620 through theconnector 612 and is re-circulated to the inside space 618 through thevalved openings 622 coupled to the ceiling 610. In some embodiments, oneor more fans may be used to exhaust the heated air out of the enclosure606 to the attic space 620 and re-circulate the air to the inside space618

FIG. 7 illustrates a top view of an example cooling system. The lateralwalls 700 and a ceiling or roof define an inside space 718. An enclosure706 defines an interior space 716. The enclosure may be connected to oneor more racks 708 in a substantially sealed manner. One or morerack-mounted units each comprising one or more cooling fans areinstalled in the rack 708. One or more valved openings 714 on thelateral walls 700 allow outside cool air to enter the inside space 718.The cool air is drawn from the inside space by the cooling fans mountedinternally within the rack-mounted units installed in the server racks,and the heated air is ejected to the interior space 716. In someembodiments, one or more air handling units 726 may draw external coolair to the inside space 718. In one embodiment, the cooling systemmeasures 60 feet wide, 255 feet long, and 16 feet high. Four enclosuresare installed in the cooling system. Eight racks are connected to eachenclosure on each side in a substantially sealed manner. Each rackcomprises 16 1U servers. The lateral wails, the ceiling, the roof, andthe enclosures may be pre-manufactured and installed on the constructionsite of the data center. Comparing with other data center designs, theexample cooling system may easier to install and more efficient tooperate.

FIG. 8 illustrates another example server cooling system comprisinglateral walls 800, a floor 802, a roof 804, an enclosure 806, a serverrack 808, and a ceiling 810. The lateral walls 800, the floor 802 andthe ceiling 810 define an inside space 818. The roof 804 and the ceiling810 define an attic space 820. One or more valved openings 822 arecoupled to the ceiling 810. There may be valved openings 824 on the roof804 and valved openings 814 on the lateral walls 800. The example servercooling system in FIG. 8 is similar to the one in FIG. 2 except that agable roof 804 is used instead of a single-sloped roof 204. A gabledroof may provide better air circulation in the attic space 818. However,the cost of building a gable roof may be higher than that of building asingle-sloped roof.

FIG. 9 illustrates another example server cooling system comprisinglateral walls 900, a floor 902, a roof 904, an enclosure 906, a serverrack 908, a ceiling 910, and outside walls 930. The example servercooling system in FIG. 9 is similar to the one in FIG. 8 except that theroof 904, the floor 902, the lateral walls 900, and the outside walls930 define a mixing space 928. The lateral walls 900, the floor 902 andthe ceiling 910 define an inside space 918. The roof 904 and the ceiling910 define an attic space 920. In some embodiments, outside cool air maybe drawn into the mixing space 928 through valved openings 914 on theoutside walls 930. The cool air is drawn to the inside space 918 by oneor more air handling units 926 coupled to the lateral wails 900. One ormore rack-mounted units each comprising a cooling fan are installed inthe rack 908. The cooling fans mounted internally within therack-mounted units draw cooling air from the inside space 918 throughthe rack-mounted units and eject heated air to the interior space 916.The heated air enters the attic space 920 through one or more connectors912 which operably connect the interior space 916 to the attic space920. In some embodiments, the heated air in the attic space 920 isexhausted to the outside through one or more valved openings 924. Inother embodiments, the heated air is drawn to the mixing space 928through one or more valved openings 922 and is mixed with the outsidecool air. In yet other embodiments, the valved openings 914, 922, and924 may be operably connected to a control system which is operable toselectively activate each valved openings. When the external air is notsuitable to be introduced to the inside space 918, the control systemcloses valved openings 914 and 924 and opens valved openings 922. Heatedair in the attic space 920 is re-circulated to the mixing space 928 andis re-circulated to the inside space 918. In other embodiments, thecontrol system monitors the temperature in the inside space 918, theattic space 920, the mixing space 928, and the temperature outside. Whenthe difference in temper among the observed temperatures reaches one ormore threshold values or other dynamic or predetermined levels, thecontrol system may selectively open or close each valved opening. Tocool the air in the inside space, one or more cooling units may be used.In some embodiments, the cooling units are installed within the mixingspace 928. In other embodiments, the cooling units are installed withinthe inside space 918. In one embodiment, the cooling units areevaporative coolers.

FIGS. 10A and 10B illustrate an example of an air handler buildingstructure 1000, including a floor 1002, a plurality of lateral walls1004, and a roof 1006. In this example, the building structure 1000 maybe pre-manufactured in a factory and assembled on the construction sitewhere a data center is to be built. As describe before, pre-manufacturedunits may significantly reduce the cost of the building structure 1000.One of the cost advantages of the air handier building structure 1000for a server cooling system is the convenience and low cost ofpre-manufacture parts of the system and the ease of installation ofpre-manufactured parts in a data center. The material of the buildingstructure 1000 includes, but is not limited to, steel, compositematerial, carbon material, or any other suitable material.

The floor 1002 in this example is a non-raised floor, which has arelative low initial construction cost compared with a raised floor. Itis understood that raised floor may be partially or completely used inthe building structure 1000 in other examples. The plurality of lateralwalls 1004 include a lower lateral wall 1004-a and an upper lateral wall1004-b opposing to each other having different respective heightsdetermined in accordance with a ratio. As shown in FIG. 10B, which isthe top-view of the building structure 1000, the plurality of lateralwalls 1004 may also include two other lateral walls 1004-c, 1004-dsubstantially perpendicular to the lower and upper lateral walls 1004-a,1004-b. The roof 1006 may be constructed in accordance with a pitchconsistent with the ratio associated with the lower and upper lateralwalls 1004-a, 1004-b. In other words, the roof 1006 is a sloped roofwith a pitch of 1:x, where x is substantially larger than one, so thatsnow builds up and melts on the roof 1006, with the heat from theinterior of the building structure 1000 accelerates the snow-meltingprocess. In one example, x equals to 6 (e.g., the pitch may be 2:12). Inthis example, the roof 1006 is a single-sloped roof (also known as ashed roof). It is understood that, in other examples, such as in FIGS. 8and 9, the roof 1006 may be a gable roof or any other suitable type ofroof.

One or more openings 1008, such as valved openings, may be located ondifferent parts of the building structure 1000, such as on one or morelateral walls 1004 and the roof 1006. In this example, the lower lateralwall 1004-a has one or more openings 1008-a through which outsidenatural air may enter the building structure 1000. In one example, thelower lateral wall 1004-a may be substantially louvered to facilitatethe outside natural air to enter the building structure 1000. In thisexample, the upper lateral wall 1004-b may have one or more openings1008-b through which air in the building structure 1000 can exit. In oneexample, a portion of the upper lateral wall 1004-b that is above theheight of the lower lateral wall 1004-a may be substantially louvered toallow air to exit the building structure 1000. Optionally, the roof 1006may also include one or more openings 1008-c through which air in thebuilding structure 1000 can exit. It is understood that, although FIG.10A shows openings 1008-b, 1008-c on both the upper lateral wall 1004-band the roof 1006, this configuration may not be necessary in otherexamples. As long as there are openings above the height of the openings1008-a on the lower lateral wall 1004-a, air in the building structure1000 can exit the building structure 1000 via natural convection.

Referring now to FIG. 10B, a first dimension L1 along a first directionis defined between the lower and upper lateral walls 1004-a, 1004-b, anda second dimension L2 along a second direction is defined perpendicularto the first direction, in this example, between the other two lateralwalls 1004-c, 1004-d. As shown in FIG. 10B, L1 is smaller than L2. Therelative length of L1 and L2 is designed such that the buildingstructure 1000 provides access to outside natural air via the one ormore openings 1008-a on the lower lateral wall 1004-a by increasing thearea-volume-ratio of the building structure 1000. In one example, L2 maybe twice of L1. Accordingly, the shape of the building structure 1000allows air within the building structure 1000 to rise via naturalconvection. In other words, the building structure 1000 is designed totake advantage of the warm air's tendency to rise to achieve “freecooling.” This natural “drafting” enhances the mechanically inducedmovement of air and therefore reduces the overall power for cooling.With the design in this example, the building structure 1000 itselfserves well as an air handler even without the traditional mechanicalcooling system (i.e., by “free cooling”).

As shown in FIG. 10A, the building structure 1000 may include a ceiling1010 that divides the interior of the building structure 1000 into afirst space 1012 and a second space 1014. In this example, the firstspace 1012, which may be used for installing servers of a data center,is defined between the floor 1002 and the ceiling 1010; the second space1014, as an attic space, is defined between the ceiling 1010 and theroof 1006. The ceiling 1010 may have one or more openings 1008-d locatedat different regions of the ceiling 1010. In this example, at least oneopening 1008-d is located near the openings 1008-a on the lower lateralwall 1004-a where the outside natural air enters the building structure1000. With such configuration, the outside natural air enters the firstspace 1012 through the openings 1008-a on the lower lateral wall 1004-aand exits the first space 1012, by natural convection, through theopenings 1008-d on the ceiling 1010 to enter the second space 1014. Theair in the second space 1014 then exits, by natural convection, throughthe openings 1008-b on the portion of the upper lateral wall 1004-babove the ceiling 1010 and/or the openings 1008-c on the roof 1006. Theair in the second space 1014 may also enter the first space 1012 throughthe openings 1008-d on the ceiling 1010 near the lower lateral wall1004-a and may be mixed with the natural air entered the first space1012.

FIG. 11 illustrates an example of a server cooling system 1100. In thisexample, the system 1100 includes a first space 1102 defined by a floor1104, one or more lateral walls 1106, and a ceiling 1108. A plurality ofservers 1110 may be installed in the first space 1102. The system 1100,in this example, also includes a second space 1112, as an attic space,defined by the ceiling 1108 and a roof 1114. One or more openings 1116,such as valved openings, may be located on at least one of the ceiling1108, the roof 1114 and at least one of the lateral walls 1106. In thisexample, the first lateral wall (e.g., a lower lateral wall) 1106-a hasone or more openings 1116-a; the ceiling 1108 has one or more openings1116-d, including at least one opening 1116-d near the lower lateralwall 1106-a; a portion of a second lateral wall (e.g., an upper lateralwall) 1106-b above the ceiling 1108 (in the second space 1112) and/orthe roof 1114 include one or more openings 1116-b, 1116-c, respectively.The openings 1116, as described above, are used to realize the movementof air between the outside space, the first space 1102, and the secondspace 1112.

In this example, the system 1100 includes an air inlet 1118 coupled withthe first lateral wall 1106-a and operable to allow outside natural airto enter the first space 1102. The air inlet 1118, in this example,includes one or more louvered openings 1116-a on the first lateral wall1106-a. The system 1100 may also include an air outlet 1120 coupled withthe second lateral wall 1106-b and operable to allow air in the secondspace 1112 to exit. The air outlet 1120, in this example, includes oneor more louvered openings 1116-b on the second lateral wall 1106-b. Thesystem 1100 may further include one or more air-handling units 1122coupled with the air inlet 1118 to draw the outside natural air and toprovide air to the first space 1102. The air-handling units 1122include, for example, a fan 1122-a, an evaporative cooling unit 1122-bconfigured to generate evaporative cooling air based on the outsidenatural air, and in some embodiments a filter 1122-c configured tofilter the outside natural air entering the first space 1102. The fan1122-a may be a speed controlled fan and is designed to keep airturbulence high, which helps mitigate temperature gradients and inducesmixing. Optionally, the system 1100 may also include one or moreuninterruptible power supply (UPS) systems utilizing kinetic storedenergy.

In this example, the system 1100 also includes a control system 1124configured to control the one or more air-handling units 1122 to provideair to the first space 1102 in accordance with temperatures measuredwithin and outside of the first space 1102. The control system 1124 mayinclude one or more devices such as a microprocessor, microcontroller,digital signal processor, or combinations thereof capable of executingstored instructions and operating upon stored data. Control systemarrangements are well known to those having ordinary skill in the art,for example, in the form of embedded system, laptop, desktop, tablet, orserver computers.

The control system 1124 may include or couple to one or more sensors(not shown) to monitor the environmental metrics such as temperature andhumidity within and outside the first space 1102. For example,temperature sensors may be deployed at different locations in the firstspace 1102, the second space 1112, and space outside the server coolingsystem 1100 to provide real-time temperatures of various locations. Inone example, hot aisle (hot row enclosure) temperature of the serverracks in the first 1102 may be used to regulate speed controlled fans;cold aisle (cold row enclosure) temperature of the server racks in thefirst 1102 and outside air temperature and humidity may be used toprovide an indication of outdoor and return air mixing efficiencies. Dewpoint sensors and/or humidity sensors may also be provided in the airinlet 1118 and the air-handling units 1122 to monitor the humility ofthe air entering the first space 1102. It is understood that, althoughthe control system 1124 in FIG. 11 is installed in the second space1112, it may be installed in other places within the server coolingsystem 1100 or outside the server cooling system 1100. In this example,the control system 1124 is operatively coupled to the air-handling units1122 and other components of the server cooling system 1100, such as butnot limited to an air-exchanging unit 1126, which may be coupled to theopenings 1214-d on the ceiling 1108 near the first lateral wall 1106-aand may be configured to draw air from the second space 1112 into thefirst space 1102 in order to mix with the outside natural air enteringthe first space 1102. The connections between the control system 1124and other components of the system 1100 may be achieved using any knownwire or wireless communication techniques.

Depending on the measured temperatures within and outside of the firstspace 1102, the control system 1124 may control the operations of theair-handling units 1122 in conjunction with other components of theserver cooling system 1100 in, for example three different working modesat three different temperature ranges.

In a first range, which is an optimal working temperature range for theservers 1110, the control system 1124 may control the air-handling units1122 in conjunction with the air-exchanging unit 1126 to directlyprovide the outside natural air into the first space 1102 to achieve theso called “free cooling.” Specifically, in this mode, the control system1124 may turn off the evaporative cooling unit 1122-b and turn on thefan 1122-a to directly draw the outside natural air into the first space1102 without extra cooling. Optionally, the control system 1124 may alsoturn on the filter 1122-c to filter the incoming natural air. In thismode, the control system 1124 may further turn off the air exchangingunit 1126 to stop mixing the incoming natural air in the first space1102 with the heated air from the second space 1112, which may increasethe temperature in the first space 1102. In one example, the first rangeis substantially between 70° F. and 85° F.

In a second range, which is lower than the first range, the controlsystem 1124 may control the air-handling units 1122 in conjunction withthe air-exchanging unit 1126 to provide air to the first space 1102based on a mixed outside natural air and air exhausted from the servers1110 through one or more openings 1116-d on the ceiling 1108 near theair inlet 1118. Specifically, in this mode, the control system 1124 mayturn off the evaporative cooling unit 1122-b and turn on the fan 1122-ato draw the outside natural air into the first space 1102. Optionally,the control system 1124 may turn on the filter 1122-c to filter theincoming natural air. In this mode, the control system 1124 may turn onthe air-exchanging unit 1126 to draw the air exhausted through theservers 1110 into the second space 1112 to the first space 1102 in orderto heat up the incoming natural air in the first space 1102. In thisexample, the air-exchanging unit 1126 may include a damper, a return fancoupled with the openings 1106-d, and a recirculation fan to help blendthe mixing air, preventing any temperature or humidity gradients. In oneexample, the second range is about below 70° F.

In a third range, which is higher than the first range, the controlsystem 1124 may control the air-handling units 1122 in conjunction withthe air-exchanging unit 1126 to provide evaporative cooling air to thefirst space 1102 based on the outside natural air drawn from the airinlet 1118 through saturated media. Specifically, in this mode, thecontrol system 1124 may turn on both the evaporative cooling unit 1122-band the fan 1122-a to draw the outside natural air into the first space1102 and cool it down by evaporative cooling. Optionally, the controlsystem 1124 may turn on the filter 1122-c to filter the incoming naturalair. In this mode, the control system 1124 may turn off theair-exchanging unit 1126 to stop mixing the incoming natural air in thefirst space 1102 with the heated air from the second space 1112.Optionally, a dew point sensor may be used in conjunction with theevaporative media of the evaporative cooling unit 1122-b to ensureadditional moisture is not added to already saturated air. In oneexample, the second range is substantially between 85° F. and 110° F.

It is noted that in any temperature range, the control system 1124 maybe further configured to selectively activate one or more of theopenings 1116-a on the first lateral wall 1106-a to control the amountof the outside natural air drawn into the first space 1102 based on thetemperatures measured within and outside of the first place 1102. Inaddition, when the measured temperature is above 110° F., additionalmechanical cooling units and air-conditioning units may be turned on toprovide extra cooling.

The first space 1102 of the system 1100 may further include at least onesubstantially enclosed interior space 1128 engaging the ceiling 1108 andopen to the second space 1112 and at least one rack 1130 engaging theinterior space 1128 in a substantially sealed manner and having theplurality of servers 1110 mounted thereon. The interior space 1128 maybe defined by an enclosure having a frame, panels, doors, and rackports. The enclosure of the interior space 1128 may be made of a varietyof materials such as steel, composite materials, or carbon materials.The enclosure creates a housing defining the interior space 1128 that issubstantially sealed from the first space 1102. The enclosure of theinterior space 1128 includes at least one rack port that allows one ormore servers 1110 installed in the racks 1130 to interface with theinterior space 1128. One or more edges of the rack port may include agasket or other component that contacts the rack 1130 and forms asubstantially sealed interface. The rack 1130 may be removably connectedto the enclosure of the interior space 1128 through the rack port in asubstantially sealed manner.

In this example, one or more servers 1110 are installed in the racks1130 such that respective front faces of the servers 1110 interface withthe first space 1102, and that respective back faces of the servers 1110interface with the interior space 1128. In this example, eachrack-mounted server 1110 may include one or more fans 1132 thereinoperable to draw air from the first space 1102 through its front faceand expel heated air to the interior space 1128 through its back face.

The server cooling system 1100 can maintain a properly mixed serversupply air in an optimal working temperature range, for example between70° F. and 85° F. and in a non-condensing relative humidity range, forexample below 85%.

FIG. 12 illustrates another example of a server cooling system 1200. Thesystem 1200 includes a first space 1202 defined by a floor 1204, aplurality of lateral walls 1206, and a ceiling 1208, and a second space1210 defined by the ceiling 1208 and a sloped roof 1212 constructed inaccordance with a pitch. One or more openings 1214, such as valvedopenings, may be located on at least one of the roof 1212, the ceiling1208, and at least one of the lateral walls 1206, that enable outsidenatural air to enter the first space 1202 and air in the second space1210 to exit by natural convection. The system 1200 may also include atleast one interior space 1216 inside the first space 1202, that issubstantially enclosed and engaging the ceiling 1208, and at least onerack 1218 engaging the interior space 1216 in a substantially sealedmanner and having a plurality of servers 1220 mounted thereon. In thisexample, one or more servers 1220 are installed in the racks 1218 suchthat respective front faces of the servers 1220 interface with the firstspace 1202, and that respective back faces of the servers 1220 interfacewith the interior space 1216. In this example, each rack-mounted server1220 may include one or more fans 1222 therein operable to draw air fromthe first space 1202 through its front face and expel heated air to theinterior space 1216 through its back face.

The building structure in FIG. 12 is similar to that in FIGS. 10A and10B, which is designed to take advantage of natural convention toenhance the mechanically induced movement of air and therefore reducethe overall energy necessary for cooling the servers. The example servercooling system 1200 in FIG. 12 is similar to that in FIG. 11 except thatsystem 1200 does not include the external air-handling units and airexchanging units such as fans and evaporative cooling unit. The aircirculation is induced by the internal fans 1222 of the servers 1220 andthe natural convection enhanced by the special designed buildingstructure. Accordingly, the total energy consumption of the system 1200in FIG. 12 may be further reduced compared with the system 1100 in FIG.1.

FIG. 13 illustrates a cross-section of another exemplary air handlerbuilding structure 1300. The air handler building structure 1300 issimilar to air handler building structure 1000, including a floor 1302,a plurality of lateral walls 1304. The floor 1302 in this exemplaryembodiment can be a non-raised floor. It is understood that a raisedfloor may be partially or completely used in the building structure 1300in other embodiments.

The air handler building structure 1300 has two roof portions 1306,symmetrically placed on either side of a protruding portion 1322. Theprotruding portion 1307 is higher than the highest part of the roofportions 1306, and placed above the center of the building incross-section. The roof portions 1306, and the protruding portion 1322extend along the air handler building structure 1300 in a directionperpendicular to the cross-section in FIG. 13.

The protruding portion 1322 has lateral walls 1324 and roof portions1326. The lateral walls 1304, 1324 and the roof portions 1306, 1326 areconstructed in a similar manner to lateral walls 1004 and the roofportions 1006.

The roof portions 1306, like the roof portions 1006 may be constructedin accordance with a pitch of 1:x, where x is substantially larger thanone, so that snow builds up and melts on the roof 1006, with the heatfrom the interior of the building structure 1300 accelerating thesnow-melting process. In one example, x equals to 6.

One or more openings 1308, such as valved openings, may be located ondifferent parts of the building structure 1300, such as on one or morelateral walls 1304 and the roof portions 1306. In this example, thelower lateral wall 1304-a has one or more openings 1308-a through whichoutside natural air may enter the building structure 1300. In oneexample, the lateral wall 1304 may be substantially louvered tofacilitate the outside natural air to enter the building structure 1300.In this example, the lateral walls 1324 of the protruding portion 1312may have one or more openings 1308-b through which air in the buildingstructure 1300 can exit. In one example, a portion of the lateral walls1324 are above the height of the lateral wall 1304 may be substantiallylouvered to allow air to exit the building structure 1300. Optionally,the roof portions 1306 may also include one or more openings 1308-cthrough which air in the building structure 1300 can exit. It isunderstood that, although FIG. 13 shows openings 1308-c on the roofportion 1306, this configuration may not be necessary in other examples.As long as there are openings 1308 above the height of the openings1308-a on the lateral wall 1304, air in the building structure 1300 canexit the building structure 1300 via natural convection.

The additional height of the one or more openings 1308-b on the lateralwalls 1324 above the height of the openings 1308-a on the lateral wall1304 increases the natural convection in the building structure 1300over that of the building structure 1000.

As shown in FIG. 13, the building structure 1300 may include a ceiling1310 that divides the interior of the building structure 1300 into afirst space 1312 and a second space 1314. In this example, the firstspace 1312, which may be used for installing servers of a data center,is defined between the floor 1302 and the ceiling 1310; the second space1314, as an attic space, is defined between the ceiling 1310 and theroof 1306 and the protruding portion 1322. The ceiling 1310 may have oneor more openings 1308-d located at different regions of the ceiling1310. In this example, at least one opening 1308-d is located near theopenings 1308-a on the lower lateral wall 1304-a where the outsidenatural air enters the building structure 1300. With such configuration,the outside natural air enters the first space 1312 through the openings1308-a on the lateral wall 1304 and exits the first space 1312, bynatural convection, through the openings 1308-d on the ceiling 1310 toenter the second space 1314. The air in the second space 1314 thenexits, by natural convection, through the openings 1308-b on theprotruding portion 1322 above the ceiling 1310 and/or the openings1308-c on the roof portion 1306. The air in the second space 1314 mayalso enter the first space 1312 through the openings 1308-d on theceiling 1310 near the lateral wall 1304-a and may be mixed with thenatural air entered into the first space 1312.

FIG. 14 illustrates a cross-section of an other example of an airhandler building structure 1400 that is similar to the buildingstructure 1300 but without the ceiling 1310 and opening 1308-d. (otherfeatures have the same labels as in FIG. 13) The natural convectiondraws air through openings 1308-a which rises through the buildingstructure 1400 and out through openings 1308-b.

The various examples of the building structures and server coolingsystems disclosed herein can achieve an almost 100% uptime availability,for example, 99.98% uptime availability for a data center facility, forexample, having a 9.0 MW critical load. The various examples of thebuilding structures and server cooling systems disclosed herein canallow for free cooling, for example, 99% of the year via the buildingstructures' unique shape and orientation, as well as server physicalconfiguration. Also, the various examples of the building structures andserver cooling systems disclosed herein can achieve about 2% annualized“cost to cool” with evaporative cooling, where “cost to cool” is theenergy (kW) expended to remove the heat generated by the data centerload as a percentage of the data center load itself. Further, thevarious examples of the building structures and server cooling systemsdisclosed herein can save, for example, about 36 million gallons ofwater used for cooling compared with conventional water-cooled chillerplant designs with comparable IT loads. The various examples of thebuilding structures and server cooling systems disclosed herein canachieve high efficiency to a target power usage effectiveness (PUE) of,for example, less than about 1.11, such as 1.08. Moreover, the variousexamples of the building structures and server cooling systems disclosedherein can achieve about 40% reduction in data center electricityconsumption relative to industry-typical legacy data centers. Forexample, for a data center with a 9 MW of critical load, variousexamples of the building structures and server cooling systems disclosedherein can reduce energy consumption of 8.6 to 18.9 million KWh per yearcompared with conventional collocated facilities. Because water-cooledchiller may not be required in the exemplary server cooling systemsdisclosed herein, there may be zero data center-related wastewatergenerated by the server cooling systems, which equals to a reduction ofabout 8 million gallons of sewer discharge per year compared withconventional water-cooled chiller plant design. Furthermore, the variousexamples of the building structures and server cooling systems disclosedherein can reduce the construction cost compared with traditionaldesigns, for example, to no more than $5M per MW and reduce theconstruction time to, for example, less than 6 months. In one example,the various examples of the building structures and server coolingsystems disclosed herein can maintain the following room environmentalrequirements: room temperature of 55° F.-90° F., no higher than 85%non-condensing relative humidity, pressure of ±0.1 inches H₂O, and 5.4°F. per hour of rate of temperature change. The various examples of thebuilding structures and server cooling systems disclosed herein canwithstand 100-year temperature and humidity conditions and extremely lowwinter temperatures while maintaining server room environmentalrequirements.

Exemplary Results

TABLE 1 2005 2006 2006 2007 2010 Type of System Standard CRAC: Watercooled site Air cooled Modular, tuned Yahoo! no economizing; builtchiller plant; chiller plant; chiller plant; Compute DX cooling systemstandard CRAC; AHU with outside next-gen AHU Coop no economizingeconomizing with outside air economizing Site Example Yahoo! Yahoo!Yahoo! existing Quincy, WA Lockport, colocation site in colocation sitein data center facility Phase 1 NY Santa Clara, CA Santa Clara, CA inWenatchee, WA KW per ton AHU 0.50 0.50 0.40 0.35 0.10 KW per ton CHW NA0.75 1.15 0.68 0.03 KW per ton CHW 0.10 0.06 0 during free cooling KWper ton DX 1.38 NA NA NA NA EXAMPLE electro/ 5,000 5,000 5,000 5,0005,000 mechanical load KW Tonnage requirement 1,420 1,420 1,420 1,4201,420 KW AHU (max) 710 710 566 497 142 KW AHU best N/A N/A 142 85 0(free cooling) KW AHU average 719 710 355 291 71 KW heat removal max1,960 1,065 1,633 965 42 (DX or CHW) KW heat removal best — — 142.0585.23 0 (free cooling) KW heat removal 1,960 1,065 968 568 21 averageTotal cooling load 2,670 1,775 1,313 859 92 KW per MW DC load % of TotalCooling 53% 36% 26% 17% 2%

TABLE 1 is a breakdown of the progression of cooling efficiency overtime by using at least some of the examples of the building structuresand server cooling systems disclosed herein. In TABLE 1 AHU representsair handling units, CHW represents chilled water, and DX representsdirect expansion. For example, by applying at least some of the examplesof the building structures and server cooling systems disclosed herein,the average power used in AHU has been reduced from 710 KW to 71 KW. Asanother example, using at least some of the exemplary disclosedembodiments, the percentage of the total cooling have been reduced overthe years from 53% in 2005, as typical industry standard, to only 2% inthe most recent experiment via YAHOO!'s Compute Coop in 2010. Thisrepresents a substantial improvement.

TABLE 2 Yahoo! Yahoo! Compute Colocation Yahoo! Coop (YCC) Data CenterData Center Data Center Facility - Facility- Facility - Santa Clara, CAQuincy, WA Lockport, NY (2006) (2007) (2010) True server load 140 89 89(watts): equivalent performance - 2 CPU cores, 4 GB RAM; 1 80 GB HDPower supply 215 93 93 efficiency loss (watts) Dist/server voltage 222 —— transformation loss (watts) UPS efficiency 252 99 97 loss (watts)Medium voltage 257 101 99 transformation loss (watts) Total power per257 101 99 example server (watts) KW cost to power 6,438 2,529 2,48925,000 servers (without cooling) KW cost to cool 2,265 434 46 serversTotal KW cost for 8,722 2,963 2,535 25,000 servers Total KW power 5,7596,187 savings versus Santa Clara CoLo PUE 1.62 1.27 1.08

TABLE 2 is a breakdown of the progression of electrical efficiency overtime by using at least some of the examples of the building structuresand server cooling systems disclosed herein. In TABLE 2, PUE representspower usage effectiveness, which is obtained by measuring the systemutility power input and the critical power consumption as close aspossible to the server loads. This information may be read and collectedfrom the installed Electrical Power Monitoring System (EPMS) using powercircuit monitors. Since all data centers in TABLE 2 may extensivelyutilize outside air cooling methods, data may be collected on a monthlybasis and annualized to account for variables such as weather, operatinghours, etc. PUE can be calculated using the following:

${P\; U\; E} = \frac{{Total}\mspace{14mu} {Facility}\mspace{14mu} {Power}}{{IT}\mspace{14mu} {Equipment}\mspace{14mu} {Power}}$

where, IT Equipment Energy is the comprehensive energy use associatedwith all of the IT equipment such as computer, storage and networkequipment along with supplemental equipment; Total Facility Energy isall facility energy use including IT equipment energy, electricaldistribution losses, cooling system energy, fuel usage, and othermiscellaneous energy use.

TABLE 2 shows that YAHOO!Lockport, N.Y. facility has a 70% improvementover the YAHOO!Santa Clara, Calif. co-location facility whenimprovements in all components in electrical efficiency path areincluded. For example, by applying at least some of the examples of thebuilding structures and server cooling systems disclosed herein, PUE hasbeen further reduced from 1.62 to 1.08, compared with an industryaverage of 2.0.

TABLE 3 Yahoo! Yahoo! Colocation Compute Data Center Yahoo! Coop (YCC)Facility - Data Center Data Center Santa Facility - Facility - Clara, CAQuincy, WA Lockport, NY PUE 1.62 1.27 1.08 Relative 26,541,30712,094,773 — energy savings for a 9 MW YCC plant (kWh/year) Averageannual 14,863 6,773 — carbon savings (tons CO₂)

TABLE 3 shows the energy and carbon savings utilizing at least some ofthe examples of the building structures and server cooling systemsdisclosed herein. In addition, minimized use of evaporative cooling ascompared to standard cooling methods may yield a 99% reduction in wateruse at the facility (and a corresponding reduction in wastewateroutflow) as compared to a traditional data center that uses water cooledchillers. The carbon savings below assumes an average U.S. carbonintensity of 0.56 tons CO₂/MWh. In other examples, the actual carbonreductions may be much lower by virtue of how clean electricity is inall three sites (0.31 tons CO₂/MWh for Santa Clara, and close to zerofor both WA state and NY state).

Two example YAHOO!data center facilities disclosed in TABLES 1-3 aredescribed in details below.

YAHOO!Data Center Facility—WA

Site Description. The existing installation at Wenatchee has proven tobe the most efficient YAHOO!data center prior to 2010. Located incentral Washington, the site was selected for its climate, with theexisting building optimized to take advantage of outside aireconomization. Air handling units (AHU) discharge into a traditionalraised floor plenum, distributing supply air to the servers.

Installation Date: 2006

Electrical: 4.8 MW, N+1 critical infrastructure with 4,800 KW staticbattery UPS and 4×2 MW diesel generator back up.Cooling System: Air Cooled Chillers and AHUs with outside aireconomizing.

Designed Target PUE: 1.25.

YAHOO!Compute Coop (YCC) Data Center Facility—Lockport, N.Y.

Site Description: The innovative design and installation of theYAHOO!Compute Coop at Lockport is the most efficient of all YAHOO!datacenters to date. Located in Lockport, N.Y., the greenfield site wasselected for its cold climate; its unique design exclusivelyincorporates outside air economization, significantly reducing supplyfan horsepower.

Installation Date: 2010.

Electrical: 9 MW, N+1 critical infrastructure with line interactive UPSsystems using kinetic stored energy and diesel generator backup. PrimaryUPS systems are deployed in 200 KW modules, allowing systems to be takenoffline when not in use.Cooling System: YAHOO!Compute Coop integrated building system coolingwith evaporative cooling.

Designed Target PUE: 1.08-1.11.

The deployment of at least some of the examples of the buildingstructures and server cooling systems disclosed herein has evidence toprove their effectiveness. Innovative building structures and servercooling systems disclosed herein can reduce risk aversion within thedata center industry (both data center designers and IT equipmentmanufacturers) for other innovations that relate to free cooling,chiller-less data centers, and broader temperature ranges—as well asexperimenting with designing data centers with closer attention tomaximizing the use of local climate conditions.

The present invention has been explained with reference to specificembodiments. For example, while embodiments of the present inventionhave been described with reference to specific components andconfigurations, those skilled in the art will appreciate that differentcombination of components and configurations may also be used. Forexample, raised subfloors, CRAC units, water chiller, or humiditycontrol units may be used in some embodiments. Seismic control devicesand electrical and communication cable management devices may also beused in some embodiments. Other embodiments will be evident to those ofordinary skill in the art. It is therefore not intended that the presentinvention be limited, except as indicated by the appended claims.

We claim:
 1. An air handler building structure, comprising: a floor; aplurality of lateral walls, including a lower and an upper lateral wallsopposing to each other having different respective heights determined inaccordance with a ratio; a roof with a pitch consistent with the ratioassociated with the lower and upper lateral walls; and one or moreopenings located on at least one of the roof and at least one of thelateral walls, wherein the shape of the building structure allows airwithin the building structure to rise via natural convection, and afirst dimension along a first direction defined between the lower andupper lateral walls relative to a second dimension along a seconddirection perpendicular to the first direction such that the buildingstructure provides access to outside natural air via one or moreopenings on the lower lateral wall.
 2. The building structure of claim1, further comprising: a ceiling having one or more openings; a firstspace defined between the floor and the ceiling; and a second spacedefined between the ceiling and the roof, wherein the outside naturalair enters the first space through the one or more openings on the lowerlateral wall, and air in the first space exits, via natural convection,through the one or more openings on the ceiling.
 3. The buildingstructure of claim 2, wherein air in the second space exits, via natural1 convection, through the one or more openings located on at least oneof the roof and at least one of the lateral walls above the ceiling. 4.The building structure of claim 2, wherein air in the second spaceenters the first space via one or more openings on the ceiling near thelower lateral wall and is mixed with the outside natural air enteredinto the first space.
 5. The building structure of claim 1, wherein thesecond dimension is greater than the first dimension.
 6. The buildingstructure of claim 1, wherein the ratio of the second dimension to thefirst dimension is two.
 7. The building structure of claim 1, whereinthe pitch is 1:x, where x is substantially larger than one, yielding asloped roof that allows snow to build up and melt and heat from interiorof the building structure accelerates the snow-melting process.
 8. Thebuilding structure of claim 7, wherein x is
 6. 9. The building structureof claim 1, wherein the lower lateral wall is substantially louvered toallow the outside natural air to enter the building structure, and theupper lateral wall has a portion above the height of the lower lateralwall substantially louvered to allow air to exit the building structure.10. The building structure of claim 1, wherein the floor is a non-raisedfloor.
 11. The building structure of claim 1, wherein the roof is one ofa single-sloped roof and a gable roof.
 12. A server cooling system,comprising: a first space defined by a floor, one or more lateral walls,and a ceiling, having a plurality of servers installed therein; a secondspace defined by the ceiling and a roof; one or more openings located onat least one of the ceiling, the roof, and at least one of the one ormore lateral walls; an air inlet coupled with a first lateral wall andoperable to allow outside natural air to enter; one or more air-handlingunits coupled with the air inlet to draw the outside natural air and toprovide air to the first space; an air outlet coupled with a secondlateral wall and operable to allow air in the second space to exit; anda control system configured to control the one or more air-handlingunits to provide air to the first space in accordance with temperaturesmeasured within and outside of the first space.
 13. The system of claim12, wherein the control system controls the one or more air-handlingunits to provide the outside natural air to the first space when thetemperatures measured within and outside of the first place is within afirst range.
 14. The system of claim 13, wherein when the temperaturesmeasured within and outside of the first place is within a second rangelower than the first range, the control system controls the one or moreair-handling units to provide air to the first space based on a mixedoutside natural air and air exhausted from the plurality of serversthrough one or more openings on the ceiling near the air inlet.
 15. Thesystem of claim 14, wherein when the temperatures measured within andoutside of the first place is within a third range higher than the firstrange, the control system controls the one or more air-handling units toprovide evaporative cooling air to the first space based on the outsidenatural air drawn from the air inlet through saturated media.
 16. Thesystem of claim 15, wherein the first range is substantially between 70°F. and 85° F., the second range is about below 70° F., and the thirdrange is substantially between 85° F. and 110° F.
 17. The system ofclaim 12, wherein the air inlet includes one or more louvered openingson the first lateral wall.
 18. The system of claim 12, wherein the airoutlet includes one or more louvered openings on at least one of theroof and the second lateral wall.
 19. The system of claim 12, furthercomprising an air exchanging unit coupled to the one or more openings onthe ceiling and configured to draw air from the second space into thefirst space in order to mix with the outside natural air entering intothe first space.
 20. The system of claim 17, wherein the control systemis further configured to selectively activate one or more of theopenings on the first lateral wall to control the amount of the outsidenatural air drawn into the first space based on the temperaturesmeasured within and outside of the first place.
 21. The system of claim12, wherein the first space comprises: a substantially enclosed interiorspace engaging the ceiling and open to the second space; and a rackengaging the interior space in a substantially sealed manner and havingthe plurality of servers mounted thereon, wherein respective front facesof the rack-mounted servers interface with the first space, respectiveback faces of the rack-mounted servers interface with the interiorspace, and each rack-mounted server includes one or more fans thereinoperable to draw air from the first space through its front face andexpel heated air to the interior space through its back face.
 22. Thesystem of claim 12, wherein the one or more air-handling units include:an evaporative cooling unit configured to generate evaporative coolingair based on the outside natural air; and a filter configured to filterthe outside natural air entering the first space.
 23. A server coolingsystem, comprising: a first space defined by a floor, a plurality oflateral walls, and a ceiling; a second space defined by the ceiling anda sloped roof constructed in accordance with a pitch; one or moreopenings, located on at least one of the roof, the ceiling, and at leastone of the lateral walls, that enable outside natural air to enter thefirst space and air in the second space to exit by natural convection;an interior space inside the first space, that is substantially enclosedand engaging the ceiling; a rack engaging the interior space in asubstantially sealed manner and having a plurality of rack-mountedservers mounted thereon, wherein respective front faces of therack-mounted servers interface with the first space, respective backfaces of the rack-mounted servers interface with the interior space, andeach rack-mounted server includes one or more fans installed thereinoperable to draw air from the first space through its front face andexpel heated air to the interior space through its back face.
 24. Thesystem of claim 23, wherein air in the first space exits, via naturalconvection, through one or more openings on the ceiling and enters thesecond space.
 25. The system of claim 23, wherein air in the secondspace enters the first space via one or more openings on the ceiling andis mixed with the outside natural air entered into the first space. 26.The system of claim 23, wherein the pitch is 1:x, where x issubstantially larger than one, yielding a sloped roof that allows snowto build up and melt and heat from the plurality of servers acceleratesthe snow-melting process.
 27. The system of claim 26, wherein x is 6.28. The system of claim 23, wherein a first of the lateral walls issubstantially louvered to allow the outside natural air to enter thefirst space, and a second of the lateral walls has a portion in thesecond space substantially louvered to allow air to exit the secondspace.
 29. The system of claim 23, wherein the floor is a non-raisedfloor.
 30. The system of claim 23, wherein the roof is one of asingle-sloped roof and a gable roof.
 31. An air handler buildingstructure, comprising: a floor; a plurality of lateral walls; a roofportion having opposing sides, each having a pitch; a protruding portionextending above the roof portion; and one or more openings located on atleast one of the roof portion, at least one of the lateral walls, andthe protruding portion, wherein the shape of the building structureallows outside natural air to enter through one or more openings on atleast one of the lateral walls via natural convection and exit throughone or more openings on at least one of the roof portion and theprotruding portion.
 32. The building structure of claim 31, furthercomprising: a ceiling having one or more openings; a first space definedbetween the floor and the ceiling; and a second space defined betweenthe ceiling and the roof portion and the protruding portion, whereinoutside air enters the first space through the one or more openings onone or more of the lateral walls, and air in the first space exits, vianatural convection, through one or more openings on at least one of theceiling, the roof portion, and the protruding portion.
 33. The buildingstructure of claim 32, wherein air in the second space exits, vianatural convection, through one or more openings located on at least oneof the roof portion and the protruding portion.
 34. The buildingstructure of claim 32, wherein air in the second space enters the firstspace via one or more openings on the ceiling near one or more of thelateral walls and is mixed with the outside natural air entered into thefirst space.
 35. The building structure of claim 31, wherein a firstdimension is defined along a first direction between a first pair ofopposing lateral walls; a second dimension is defined between a secondset of opposing lateral walls aligning along a second directionperpendicular to the first direction; the first dimension relative tothe second dimension is such that the building structure provides accessto outside natural air via one or more openings on at least one of thelateral walls, wherein the second dimension is greater than the firstdimension.
 36. The building structure of claim 32, the shape of thebuilding structure causes the air to be drawn, from the first space,through one or more servers in the first space, via natural convection,and hot air yielded by the servers to exit from the first space to thesecond space.
 37. The building structure of claim 31, wherein the pitchis 1:x, where x is substantially larger than one, yielding a sloped roofthat allows snow to build up and melt and heat from interior of thebuilding structure accelerates the snow-melting process.
 38. Thebuilding structure of claim 37, wherein x is
 6. 39. The buildingstructure of claim 32, wherein at least one of the lateral walls issubstantially louvered to allow the outside air to enter the buildingstructure; and at least one of the lateral walls has a portion above theceiling substantially louvered to allow air to exit the buildingstructure.
 40. The building structure of claim 31, wherein the floor isa non-raised floor.